Theme 4: GEOLOGY OF THE LITHOSPHERE
Key Idea 1: The loss of heat through the Earth's
surface leads to cooling and the development of
an outer shell of high strength known as the
lithosphere underlain by a layer of lower
strength known as the asthenosphere.
Lithosphere
Asthenosphere
Surface Heat Flow
Continental Geotherm
Oceanic Geotherm
Mantle Solidus Curve
Seismic Low Velocity Zone
P+S wave velocity-depth Curves
1300C Isotherm
Variations in thickness of Lithosphere
Continental Shields
Oceanic Basins
Oceanic Crust
Continental Crust
Moho
Theme 4: GEOLOGY OF THE LITHOSPHERE
Key Idea 2: Oceanic lithosphere is formed at
divergent (constructive) plate boundaries and
destroyed at convergent (destructive) plate
boundaries.
Oceanic crust seismic layers 1,2,3
Abyssal Sediments
Pillow Lavas
Sheeted Dykes
Underplated Gabbro
Ophiolites
Troodos Massif, Cyprus
Lizard Peninsula, Cornwall
Rate + direction of Sea Floor Spreading
Palaeomagnetic Anomalies
Radiometric Dating
Ocean floor age distribution maps
Mantle plumes (hotspots)
Variations in oceanic crust heat flow
Thickening of oceanic lithosphere
Subduction zones
Island arc magmatism
Cordilleran magmatism
Marginal ocean basins
Back-arc spreading
Continental rifting
J Tuzo Wilson cycle
Iapetus Ocean + Caledonian Orogeny
Theme 4: GEOLOGY OF THE LITHOSPHERE
Key Idea 3: A wide range of lithospheric
processes contributes to the formation and
deformation of continental crust.
Low density continental crust
Age distribution of crustal rocks
Orogenic belts
Continent-continent collision
Continent-Island Arc collision
Cordilleran mountain belts
Ophiolites + Accretionary Prisms
Crustal melting + Granite magmatism
Crustal thickening
Delamination
Isostatic uplift
Gravitational collapse
Brittle deformation
Ductile deformation
Flexural (Parallel) folds
Flow (Similar) folds
Nappes
Thrusts
Extensional sedimentary basins
N.Sea Viking Graben
Foreland basins
Po Basin, Italy